The BMW 635d Convertible, part of the E64 facelift series produced from 2007 to 2010, represented a compelling blend of luxury, performance, and diesel efficiency within the 6 Series lineup. Positioned as a mid-range offering, it slotted between the gasoline-powered 630i and the higher-performance 650i. This variant aimed to provide a refined grand touring experience with the added benefit of improved fuel economy, appealing to drivers seeking a sophisticated convertible without sacrificing driving pleasure. The E64 facelift brought styling revisions and updated technology compared to the pre-2007 models, enhancing the overall appeal of the 6 Series Convertible.
Technical Specifications
| Brand | BMW |
| Model | 6 Series |
| Generation | 6 Series Convertible (E64, facelift 2007) |
| Type (Engine) | 635d (286 Hp) Steptronic |
| Start of production | 2007 |
| End of production | 2010 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Cabriolet |
| Seats | 4 |
| Doors | 2 |
| Fuel consumption (urban) | 9.6 l/100 km (24.5 US mpg) |
| Fuel consumption (extra urban) | 5.8 l/100 km (40.6 US mpg) |
| Fuel consumption (combined) | 7.2 l/100 km (32.7 US mpg) |
| CO2 emissions | 190 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 6.6 sec |
| Acceleration 0 – 62 mph | 6.6 sec |
| Acceleration 0 – 60 mph | 6.3 sec |
| Maximum speed | 250 km/h (155.34 mph) |
| Emission standard | Euro 4 |
| Weight-to-power ratio | 6.5 kg/Hp |
| Weight-to-torque ratio | 3.2 kg/Nm |
| Power | 286 Hp @ 4400 rpm |
| Torque | 580 Nm @ 1750-2250 rpm (427.79 lb.-ft.) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | M57D30 |
| Engine displacement | 2993 cm3 (182.64 cu. in.) |
| Number of cylinders | 6 |
| Engine configuration | Inline |
| Cylinder Bore | 84 mm (3.31 in.) |
| Piston Stroke | 90 mm (3.54 in.) |
| Compression ratio | 17:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Engine oil capacity | 7.7 l (8.14 US qt | 6.78 UK qt) |
| Coolant | 8.2 l (8.66 US qt | 7.21 UK qt) |
| Kerb Weight | 1860 kg (4100.6 lbs.) |
| Max. weight | 2260 kg (4982.45 lbs.) |
| Max load | 400 kg (881.85 lbs.) |
| Trunk (boot) space – minimum | 450 l (15.89 cu. ft.) |
| Fuel tank capacity | 70 l (18.49 US gal | 15.4 UK gal) |
| Length | 4820 mm (189.76 in.) |
| Width | 1855 mm (73.03 in.) |
| Height | 1374 mm (54.09 in.) |
| Wheelbase | 2780 mm (109.45 in.) |
| Front track | 1558 mm (61.34 in.) |
| Rear (Back) track | 1596 mm (62.83 in.) |
| Drag coefficient (Cd) | 0.30 |
| Minimum turning circle | 11.4 m (37.4 ft.) |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears | 6 |
| Gearbox type | Automatic transmission |
| Front suspension | Double wishbone |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Hydraulic Steering |
| Tires size | 245/50 R17 99W RSC |
| Wheel rims size | 7.5 J x 17 |
Powertrain & Engine Architecture
The heart of the 635d was the M57D30, a 3.0-liter inline-six diesel engine. This engine was a mainstay in BMW’s model range during the mid-2000s, known for its robust construction and strong torque output. The M57D30 utilized a common rail direct injection system, delivering fuel at extremely high pressures for optimized combustion. A variable geometry turbocharger (VGT) and intercooler further enhanced performance, providing a broad torque curve and minimizing turbo lag. The engine produced 286 horsepower at 4400 rpm and a substantial 580 Nm (427.79 lb-ft) of torque between 1750 and 2250 rpm. This torque figure was a key characteristic, providing effortless acceleration and strong in-gear performance. The “Steptronic” transmission was BMW’s name for its 6-speed automatic gearbox. It offered both fully automatic operation and a manual shift mode, allowing drivers to have more control over gear selection. The transmission was tuned to complement the engine’s torque characteristics, providing smooth shifts and responsive performance.
Driving Characteristics
The 635d Convertible offered a distinctly different driving experience compared to its gasoline-powered siblings. While lacking the outright top-end power of the 650i, the 635d excelled in providing strong, usable performance across a wider range of engine speeds. The abundant torque meant that overtaking maneuvers were executed with ease, and the car felt relaxed and composed even when fully loaded. The automatic transmission, while smooth, wasn’t as quick-shifting as some of the more modern transmissions available today. However, it was well-suited to the engine’s characteristics, providing a comfortable and refined driving experience. Compared to the manual transmission options available in other 6 Series models, the automatic version prioritized comfort and ease of use over outright driver engagement.
Equipment & Trim Levels
The 635d Convertible came standard with a generous array of features, befitting its luxury positioning. Standard equipment typically included leather upholstery, automatic climate control, power-adjustable seats with memory function, a premium sound system, and xenon headlights. Optional extras included features such as active steering, comfort seats with ventilation and massage functions, a head-up display, and a variety of interior trim options. The exterior could be customized with different wheel designs and paint colors. The interior trim levels offered a range of wood veneers and aluminum accents, allowing buyers to personalize the cabin to their preferences.
Chassis & Braking
The E64 6 Series Convertible featured a sophisticated chassis designed to provide a balance of comfort and handling. The front suspension utilized a double wishbone design, while the rear employed an independent multi-link setup. This configuration helped to minimize body roll and provide precise steering response. The 635d was equipped with ventilated disc brakes on all four wheels, providing ample stopping power. An Anti-lock Braking System (ABS) was standard, enhancing safety and stability during hard braking. The steering was a hydraulic rack and pinion system, offering a good balance of feel and assistance.
Market Reception & Comparison
The 635d Convertible was generally well-received by automotive critics. It was praised for its refined driving experience, strong performance, and impressive fuel economy. Compared to the 630i, the 635d offered significantly more torque and better fuel efficiency. However, it didn’t quite match the outright performance of the 650i. The diesel engine was also noted for being quieter and more refined than some of its competitors. Fuel economy was a significant selling point, with the 635d achieving combined fuel consumption figures of around 32.7 US mpg, making it a more economical choice for long-distance driving.
Legacy
The M57D30 engine, found in the 635d, has proven to be a remarkably durable and reliable powerplant. With proper maintenance, these engines can easily exceed 200,000 miles. The 635d Convertible remains a desirable used car today, appealing to buyers seeking a stylish and comfortable grand tourer with good fuel economy. However, potential buyers should be aware of the potential for diesel particulate filter (DPF) issues and the importance of regular maintenance. The E64 6 Series, including the 635d, has become a modern classic, appreciated for its elegant design and refined driving experience.
